Law enforcement sources have identified the Manhattan attacker as Sayfullo Saipov, 29. US President Donald Trump denounced him as “very sick” and a “deranged person.”

Authorities inspect the scene following a shooting incident in New York on Tuesday.(AFP Photo)

A pickup driver killed eight people in New York on Tuesday, mowing down cyclists and pedestrians before striking a school bus, in the city’s first deadly attack blamed on terror since September 11, 2001.

Law enforcement sources identified the perpetrator as Sayfullo Saipov, 29. US President Donald Trump denounced him as “very sick” and a “deranged person.”

Experts say the tactic of mowing people down avoids the need to obtain any explosives or weapons and can be carried out by a ‘lone-wolf’ attacker without using a network of fellow militants – all lessening the risk of alerting security agencies.

Some feel that these low-tech, lone wolf operations can have the same psychological impact as larger, more sensational attacks.

Charlie Winter, a senior research fellow at the London-based International Centre for the Study of Radicalisation and Political Violence, told The Associated Press what makes such attacks so frightening is the relatively low barriers to entry. The method was embraced by al Qaeda before being revitalised by IS.

Lone wolves have been an old problem, but recently, the number of attacks by them has grown.

According to a study by Mark Hamm and Ramon Spaaj, they are much more prone to mental illness. More than 40% of the attacks they had in their database were carried out by people with some form of mental illness.

Here are the profiles of a few ‘lone-wolf’ terrorists who carried out attacks recently:

Manchester attack – May, 2017: A college dropout turned bomber

Salman Abedi, the suicide bomber who killed 22 people in an attack on a pop concert in Manchester, was a business student who dropped out of university.

Born to a devoutly Islamic Libyan family in Britain’s third biggest city, newspapers said he was known to the security services and the Financial Times said he had turned to radical Islam in recent years.

Abedi worshipped at a suburban mosque, where his father was a well-known face who sometimes performed the call to prayer.

One member of Manchester’s Libyan community told The Guardian newspaper: “He was such a quiet boy, always very respectful towards me.

“His brother Ismael is outgoing, but Salman was very quiet. He is such an unlikely person to have done this.”

One senior figure from the mosque however, Mohammed Saeed, told The Guardian that when he once gave a sermon denouncing terror, Abedi stared him down.

“Salman showed me a face of hate after that sermon,” Mohammed Saeed said of the 2015 encounter.

“He was showing me hatred.”

Abedi began studying business and management at Salford University in Manchester in 2014, a source told the Press Association news agency, but he dropped out after two years and did not complete his degree.

He did not live in university accommodation, had not been in any trouble at the university, was not on any radar for pastoral or social care and was not known to have participated in any university societies.

Westminster attack – March, 2017: A ‘nice guy’ turned extremist

Four people were killed and at least 20 injured in March this year after a man drove his car into pedestrians on Westminster Bridge before attacking a policeman close to the British Parliament.

File photo of Khalid Masood being treated by emergency services outside the Houses of parliament in London.
(AP File Photo)

The attacker was identified as 52-year-old former convict Khalid Masood.

Born on Christmas Day 1964 in Kent in southeast England, Masood had been living in the West Midlands. The police said he was a British citizen.

British media described Masood as a Muslim convert, with one source telling Sky News he was a “very religious, well spoken man”. “You couldn’t go to his home in Birmingham on Friday because he would be at prayer,” said the person who Sky said met Masood in a professional capacity.

“He was a nice guy. I used to see him outside doing his garden,” Iwona Romek, a former neighbour of his, told the Birmingham Mail.

“He had a wife, a young Asian woman and a small child who went to school,” she said.

Berlin attack – December, 2016: Attacker drank alcohol, never prayed

In his impoverished Tunisian hometown, Anis Amri drank alcohol and never prayed, his brothers say. Then after joining the wave of migrants crossing the Mediterranean, he ended up in an Italian jail, only to emerge an utterly changed man.

He was the prime suspect an attack on a Berlin Christmas market and two of his brothers, Walid and Abdelkader, fear the failed asylum seeker may have been radicalised by radical Islamists while he spent almost four years behind bars.

“When he left Tunisia he was a normal person. He drank alcohol and didn’t even pray,” Walid told the TV channel. “He had no religious beliefs. My dad, my brother and I all used to pray and he didn’t.”

The Islamic State said a Tunisian man who barrelled his truck into a crowd in the French resort city of Nice was a “soldier” of the group, though the veracity of the claim couldn’t immediately be determined.

A minister confirmed the attacker “had not been known to the intelligence services because he did not stand out... by being linked with radical Islamic ideology”. “It seems he was radicalised very quickly,” the minister said.

Information suggested 31-year-old Mohamed Lahouaiej Bouhlel was a troubled, angry man with little interest in the ultra-puritanical brand of Islam. Bouhlel’s neighbours said he had a tense personality and was “frightening” to some extent.

Eighty-four people, including 10 children and teenagers, were killed and 200 were wounded when Bouhlel slammed his 19-tonne truck into a throng of spectators on Nice’s seaside boulevard as the traditional July 14 national day fireworks celebration was ending.

Bouhlel was born in Msaken of Tunisia, but moved to France years ago and was living in the country legally, working as a delivery driver.

He had a series of run-ins with the law for threatening behaviour, violence and theft over the past six years. In March, he was given a six-month suspended sentence by a Nice court for a road-rage incident.

Neighbours described the father of three as a volatile man, prone to drinking and womanising, and in the process of divorcing his wife. Bouhlel had violent episodes during which “he broke everything he found around him”.

“From 2002 to 2004, he had problems that caused a nervous breakdown. He would become angry and he shouted... he would break anything he saw in front of him,” Mohamed Mondher Lahouaiej Bouhlel told BFM television.

“Each time he had a crisis, we took him to the doctor who gave him medication,” he said.

“What I know is that he didn’t pray, he didn’t go to the mosque, he had no ties to religion,” said the father, noting that Bouhlel didn’t respect the Islamic fasting rituals during the month of Ramzan.

Anders Behring Breivik came across as your average guy but behind his courteous exterior lurked one of history’s most gruesome killers, fuelled by a hatred of multiculturalism and Islam.

Norwegian mass killer Anders Behring Breivik makes a Nazi salute as he arrives to a makeshift court in Skien prison’s gym on March 15, 2016 in Skien, 130 km south west of Oslo.
(AFP file photo)

Tall, blond and with piercing blue eyes, the rightwing extremist confessed to killing 77 people in July, 2011, when he gunned down youths attending a Labour party camp after setting off a bomb outside the government offices in Oslo.

On his Facebook profile, Breivik describes himself as “conservative”, “Christian”, and interested in hunting and video games like “World of Warcraft” and “Modern Warfare 2”, which, he later revealed, he used to train for his deadly rampage.

He called his actions “cruel but necessary”, a plan he apparently spent years plotting and carried out alone. He became a textbook example of the “lone wolf” who lived a reclusive life in an apartment with his mother before renting a farm, a move that enabled him to acquire the fertilisers he needed to build his bomb.

“For me he just looked like your average guy. He could easily go unnoticed,” a neighbour told AFP. “A well-kept Norwegian that no one would suspect.”

A first psychiatric examination carried out last year found him to be suffering from “paranoid schizophrenia” and criminally insane. But a second opinion found him to be sane, paving the way for a possible prison sentence.